Approaches and limitations of medication delivery in patients with enteral feeding tubes

The hypertonicity of liquid medications must be evaluated in conjunction with the required dosage volume. Some medications require a minimal dosing volume and can be adequately diluted in gastric fluids or tube-flush volumes to a tolerable osmotic load. Other medications such as diphenoxylate, loperamide, and paregoric have a pharmacologic influence on motility and can be administered undiluted into the small bowel. Still others can require dilution to a final volume of 4 to 10 oz to reduce osmolality to a level tolerable by the GI tract. Bolus administration of a large volume of medication is impractical for many patients, especially if it must be administered three or four times a day. For these patients, an alternate route of drug administration is often preferable. In some instances, the IV route is most appropriate. In others, crushing the appropriate oral form, mixing it in a slurry with a suitable diluent, and administering the slurry through the feeding or NG tube can be an acceptable alternative. Regardless of the method of drug delivery, one must be cognizant of the limitations of the administration strategy, the potential for complications that can result from the administration of a medication by the enteral route, and alternative means of medication administration, should complications ensue. A vast number of pharmaceutical products are marketed in a wide array of dosage forms. For these reasons, a pharmacist or other knowledgeable healthcare provider should be consulted for information regarding product availability, bioavailability, compatibility, and potential for drug-nutrient interactions when drugs are given in conjunction with enteral feeding.